1. Field of the Invention
The present invention relates to a dispensing apparatus and a dispensing method in which a syringe having a piston performs a liquid sucking/discharging operation to dispense the liquid, and to an analyzer.
2. Description of the Related Art
Conventionally, a dispensing apparatus which drives a piston to suck liquid into a syringe and discharge the liquid from the syringe (see Japanese Patent Application Laid-Open No. H7-333231), and an analyzer including the dispensing apparatus have been known. The piston is generally connected to a rotation motor via a rotation-translation converting mechanism such as a ball screw, and a translatory movement converted from a rotational movement of the rotation motor allows a liquid sucking/discharging operation. The dispensing apparatus controls the rotation of the rotation motor to control the liquid dispensing operation.
However, in such a dispensing apparatus using the syringe, the amount of liquid dispensed from the syringe varies depending not only on a moving distance of the piston but also on other conditions. Therefore, the dispensing apparatus only with a setting of the moving distance of the piston has a variation in the amount of liquid dispensed from the syringe. Such a variation in the dispensed liquid amount causes, in some cases, an incorrect analysis on the liquid in the dispensing apparatus.